Baseboard heater



Aug. 28, 1962 D. KNOLL ETAL BASEBOARD HEATER 2 Sheets-Sheet 1 FiledApril 14, 1959 Aug. 28, 1962 D. KNOLL ETAL BASEIBOARD HEATER 2Sheets-Sheet 2 Filed April 14, 1959 United States Patent 3,ll,816BASEBOARD HEATER David Knoll, Bayside, and Albert Greenhaus, Brooklyn,

N.Y., assignors t0 Ber-k0 Electric Manufacturing Corporation, QueensVillage, N.Y., a corporation of New York Filed Apr. 14, 1959, Ser. No.806,312 8 Claims. (Cl. 21934) The present invention pertains toimprovements in heating apparatus and more particularly concerns a noveland improved heater of the baseboard type.

Among the various applications of localized electric heating onecategory is that involving the baseboard heater located at the foot orbase-board zone of the wall. Prior known baseboard heaters have not beenfound satisfactory because of unduly high localized temperatures inorder to obtain sufiicient heating effect, danger to children, pets andfurniture, high heat loss to the wall behind the heater and the creationof local convection currents of high temperature and relatively smallvolume with resultant uneven heating and a tendency to cause smudging ofthe wall above the heater. Other defects encountered have beendiiliculty of installation and servicing, undue obtrusiveness orunsightly appearance and the creation of noise due to contraction andexpansion in the apparatus under temperature changes.

Accordingly one of the objects of the invention resides in the provisionof novel and improved apparatus which overcomes the foregoingdisadvantages of prior devices and provides additional advantages thatwill become evident from the description of the invention and theaccompanying drawings.

Another object of the invention resides in the provision of a baseboardheater characterized by large air flow with relatively low surfacetemperature.

A further object of the invention resides in the provision of abaseboard heater in which a current of relatively cool air is maintainedbetween the main heating chamber and the wall behind it, thus reducingheat loss to the wall, increasing useful heat output and creating alayer or air curtain between the main convection output and the wallabove the heater by which any tendency toward smudging is materiallyreduced if not entirely prevented.

Another object of the invention resides in the provision of a heaterhaving a novel and improved arrangement and organization of elementsfunctioning to eliminate noise during thermal expansion and contraction,and by which installation or removal of the heat source is facilitated.

A further object resides in the provision of an improved baseboardheater including means for accurate thermostatic regulation andmodulation.

A further object resides in the provision of improved mounting means forbaseboard heaters by which the device may be quickly and easily securedto the Wall in top sealing relation.

A further object of the invention resides in the provision of animproved baseboard heater including an improved readily removable frontclosure means allowing ready access to the heat source and itselectrical connections.

Another object resides in the provision of improved baseboard heatingapparatus of the above nature which is compact, attractive inappearance, and readily adaptable to a wide range of space decors andheating requirements.

Other objects and advantages of the invention will become evident fromthe following description and accompanying drawings, in which "iceFIGURE 1 is a perspective exterior front view of one embodiment of theinvention;

FIGURE 2 is a perspective view of a modified embodiment of the inventionincluding thermostatic control;

FIGURE 3 is an exploded perspective view of the right end portion of theembodiment shown in FIGURES 1 and 2, illustrating the novel structureand relationship of the component parts;

FIGURE 4 is a cross-sectional view of the heater of FIGURE 1 taken alongthe line 4-4 thereof and showing the cooperation of the heater With thesupporting wall;

FIGURE 5 is a front view partly in section of the heater of FIGURE 1with the front closure removed;

FIGURE 6 is an enlarged cross section of the heating element containersleeve and a diifusing fin;

FIGURE 7 is a simplified electrical diagram illustrating one arrangementof a heating element with the control thermostat; and

FIGURE 8 is a modified circuit diagram illustrating an arrangementutilizing a modulating thermostat, with a heater in accordance with theinvention.

Referring to FIGURE 1, the numeral 10 generally designates a baseboardheated adapted to be installed at the foot of a wall 11. The housing ofthe device includes a main longitudinal supporting structure 12 to whichend plates 13 are secured, a front closure plate 14, and a short frontclosure plate 15 at one end of and matching the main closure plate ingeneral contour. The embodiment of the invention denoted by the numeral16 in FIGURE 2 is the same as that of FIGURE 1 except for greater lengthand the inclusion of a second short closure plate 17 accommodatingexterior adjusting parts of a thermostat is. The main configurations andrelationships of the component parts of the device, which aresubstantially the same in all embodiments, are shown in detail inFIGURES 3, 4 and 5.

Referring to FIGURES 3 and 4, it will be seen that the supportingstructure 12 includes a flat vertical rear Wall 18, a forward andupwardly sloping portion 15 above the rear wall portion, and arearwardly and upwardly sloping portion 20 leading to a narrow flat top21, the latter having at its rear edge a downwardly turned flange 2.2.The bottom zone of the plate 12 is formed as a rearwardly struck channel23 adapted to be an chored to the wall 11 by fastening means extendingthrough holes 24 as hereinafter set forth. The rearwardly sloping upperportion 20 is provided with perforations 25 throughout its length, and anarrow band of similar perforations 26 occupies the extreme bottom zoneof the rear wall portion 18.

Forwardly extending brackets 27 are secured in longitudinally spacedrelationship on the vertical rear wall 18, the number of such bracketsbeing dependent on the length of the particular model of the device,i.e. the embodiment in FIGURE 1 contains two brackets 27, while theembodiment shown in FIGURE 2 includes three brackets. Each bracket 27 isformed with a recess comprising a front entry slot 28 and an innerportion extending downwardly to form an arcuate supporting saddle 29(see FIGURE 3). Each bracket also has a small latching tab or extension30 depending from the lower front corner thereof and a similar upwardlydirected tab 31 on the upper edge of the bracket and spaced from thefront corner.

An outlet or junction box 32 is formed in one end of the housingstructure 12 and the inner face 13 has a circular opening 33 in generalaxial alignment with the retaining saddles, 29 in the brackets 27. Inthe embodiment shown in FIGURE 2, a second similar box 34 is provided atthe other end of the housing.

The main front closure plate 14 consists of an outwardly inclined faceportion 35 and a relatively narrow rearwardly inclined upper portion 36which terminates in a downwardly curved inner edge 37 adapted to hookover the upper tabs 31 on the brackets 27, as shown in FIGURE 4.Similarly, the lower edge 38 of the closure plate 14 is turned inwardlyand provided with an upwardly formed channel 38' constituting a snaplatch for engagement with lower tabs 30 on the brackets 27 also as shownin FIGURE 4. Small buffers 55 of thin heat-proof resilient tape such asfiber-glass or the like are provided in the joints between the plate 14and bracket tabs, for purposes hereinafter explained. Thus in operativeposition the closure plate 14 is firmly retained and supported on thebrackets 27 in snap relation, the plate having suflicient resilience tofacilitate installation and removal for servicing, cleaning and otherpurposes and at the same time have ample strength to prevent accidentalloosening or removal.

The inclined face portion 35 of the closure plate 14 is providedthroughout with perforations 39 and 46 which provide for the flow of airinto and out of the housing.

The short end closure plates 15 and 17 while matching plate 14 ingeneral contour and design are adapted to be secured in place by screws41 engaging expanded sockets 42 formed in the lower edges of thejunction boxes 32 and 34, the downwardly formed upper flanged edges ofthese plates being hooked over small retaining members 43 struckupwardly on the upper edges of the boxes.

In the illustrated embodiments of the invention, the heat sourceincludes a suitable elongated resistance unit 44 (see FIGURE 3)insulatedly encased in a metallic tube or sheath 45. The heating elementmay be formed of any suitable material as for instance heavy-dutynickelchromium wire or the like contained in ceramic tubing and may beprovided with various alternative circuit arrangements as hereafterexplained in connection with diagrams shown in FIGURES 6 and 7.

A large number of metal fins 46, preferably of rectangularconfiguration, are secured in spaced relation on the tube 45 todistribute the heat therefrom. The structure of the joints between thetube and fins is shown in enlarged fragmental detail in FIGURE 6, thethickness of the metal sections being somewhat exaggerated for clarityin illustration. While the fins may be attached to the tube in anydesired manner in the instant illustration, they are formed withcircularly corrugated inner rims 47 into which the tube 45 is expanded,thus establishing compression contact joints of high heat transmittingability as well as permanently locking them on the tube. The fins 46 arealso double-embossed in staggered checkerboard pattern as indicated at48 to increase the heat emitting areas and also stiffen the thin metalfins.

To avoid undue complication of the drawings, only fragments of embossedpattern are shown in FIGURE 3, but it will be understood that all finsare so embossed throughout substantially their entire areas.

Referring again to FIGURES 3 and 4, the numeral 49 denotes a mountingstrip adapted to be attached directly to the wall 11. This strip orbracket, which may be slightly shorter than the main housing, is formedwith the general cross-sectional shape of a snap-latch, the rearwardlysloping upper portion 50 thereof terminating in a forwardly curved lip51.

When the device is to be installed, the mounting strip 49 is firstsecured to the wall 11 by screws 52, location of the strip being readilymade by means of a suitable template which determines the proper heightof the device above the floor 53 (see FIGURE 4). Provision having beenmade for current supply for the device, as for example an armored cableand cooperating connector 54, the housing is snapped into place on themounting strip with the rear flange 22 of the main plate 12 being moveddownwardly into compressive retaining position between the wall 11 andthe lip 51 of the strip 49. A thin layer of resilient tape 56, FIGURE 4,enveloping the flange and secured thereto during manufacture, forms acushion seal between the flange and both the wall 11 and the bracket lip51 which contributes both to proper air current control and to noiseprevention, as will be set forth hereafter in greater detail. The mainplate 16 having been placed in proper position on the mounting strip asnoted, screws 57 are inserted through the lower channel 23 to anchor thelatter to the wall 11.

It will be understood, however, that the main support and location areprovided by the strip 49 which may be placed at any convenient height tomeet specific requirements; thus the bottom of the channel 23 need notextend to the floor but may be located at any desired distance above thelatter, for example to clear existing corner moldings and the like.

The mounting of the heating unit in the housing whether made at the timeof installation or during prior assembly, consists in moving the unitinward through the front slots 23 in the brackets 27, after Which theunit is lowered until the tube drops into the arcuate saddles 29 asshown in FIGURES 4 and 5, and the brackets 27.

In the single-ended embodiment of the invention as illustrated in FIGURE5, the leads 5S and 59 of the heating element extend through the opening33 into the junction box 32 and are connected with the supply conductors60 and 61 entering through the connector 54. A ground connector 62,electrically joined to the heater core tube,

is connected by means of a screw 63 to the main housingplate 16. Thefront closure plates 14 and 15 are secured in position as previouslydescribed, and the device is ready for operation.

For clarity in explanation, the foregoing assembly steps were describedas being performed on installation. However, it will be obvious that theassembly of the main housing members and the heating unit mayadvantageously be provided at the factory or point of distribution, sothat the installation of the unit proper entails only snapping thelatter over the mounting strip 49 and anchoring it to the wall,completing the electrical connections in the junction box 32, andclosing the latter by means of its plate 15.

In the forms of the invention embodying double-ended construction, asexemplified in FIGURE 2, the windings and connections of the heatingelement 44 are such as to provide a wide degree of flexibility infulfilling various requirements as to heating capacity, degree ofregulation, and ready adaptability to differing installation locationsand available current supply facilities. Typical electrical arrangementsto carry out these and related advantages are shown diagrammatically inFIGURES 7 and 8.

In the form illustrated in FIGURE 6 the two windings 64 and 65 of theheating element 44, instead of being internally connected and providedwith a single pair of exterior leads 58 and 59 at one end of the tube 45as shown in FIGURE 5, have separate leads 66 and 67 at the other end ofthe unit, these leads extending into the second junction box 34, wherethey are connected to a suitable thermostat 62.

In the embodiment illustrated in FIGURE 8, the heating element 44includes a second pair of windings 68 and 69 provided with right-handand left-hand lead pairs 70 and 71, thus forming a dual-circuit heatingelement. In the case shown, the left-hand leads 71 are joined by asuitable connector or splice 72 within the junction box 34, while theright-hand leads 70 are connected one via an exterior wall thermostat74, to the main current sup ply conductors 6t} and 61. Similarly thefirst windings 64 and 65 are connected in series by a connector orsplice '73 and are also connected across the supply conductors 6d and61, but include in series connected thermostat 41, the latter in thisillustrative case being mounted in the right-hand junction box 3:2. Thusit will be seen that the heating unit comprises two parallel heatingcircuits, one controllable by the built-in thermostat and the other bythe wall thermostat 74. In the usual mode of operation with thisarrangement, the main heating function is carried on by the firstelement circuit under control of the thermostat 41, with the secondcircuit cutting in when added heat is required as detected by themodulating wall thermostat 74. It will be evident that the inherentflexibility of the invention as to electrical and mechanical structuralarrangement renders it readily adaptable to various other controlcombinations to suit particular service conditions and that beside theobviously advantageous comfort feature the double heating elementprovides long service life when used with either modulating orconventional controls.

In operation of this novel and improved heater the paths of theconvection currents are as indicated by arrows in FIGURE 4. The air tobe heated enters the heating chamber at the bottom of the housing belowthe closure plate 14, passes upward through and about the finned heatingunit, is deflected forward by the imperforate sloping portion 19 of thesupporting structure 16, and emerges partly through the Wide opening 75above the closure plate and partly through the perforations in thelatter. This air stream is augmented by a large volume of air whichflows inward through at least part of the perforations 39 in theinclined face 35 of the closure plate 14. The flow of air into and outof the perforations 39 and 40 is governed at least in part by thetemperature of the heating element and functions to maintain at leastthe lower part of the plate 35 at a relatively low temperature. In thisway injury to individuals and furniture that may be moved in contactwith the heater is minimized.

Referring again to FIGURE 4, it will be seen that the contour of themain housing plate 16 provides a space 76 between the rear wall 18 ofthe heating chamber and the room wall 11 on which the device is mounted.The previously described narrow band of perforations 26 affords a bottominlet to the space 76 while top egress is provided by the perforations25 in the upper portion 20 of the housing structure. When the device isin operation, any leakage of heat through the rear portion 18 of themain housing structure is caused by the air in the space 76, creating asecondary convection current therein which enters through the bottomperforations 26, moves upward through the space or fiue 76 and emergesthrough the top perforations 25. Thus a gently moving curtain ofrelatively cool air is established between the wall 11 and the mainheater chamber, insulating the wall against significant heat absorptionand dangerous temperature rise, while at the same time conserving theotherwise wasted heat to augment the previously described mainconvection output; furthermore the secondary air current functions tocool the top of the heater while passing through the cavity 76a thusprotecting the top of the heater and wall joint from excesstemperatures. As another advantage of the secondary convection current,it will be observed that this current on emergence also creates ineffect a relatively cool and gently moving exterior air curtain betweenthe heated air and the wall above the unit, which substantially preventssignificant wall smudging.

A common fault of prior heating devices has been the tendency togenerate noise with changing temperatures. Such noise frequently arises,for instance, in metal-tometal joints and particularly in cases whereinfrictional gripping initially resists movement due to unequalcontraction or expansion until the forces of the latter overcome therestraint, whereupon sudden release causes snapping, creaking orcrackling sounds. In the present invention such noise is substantiallyprevented.

In the case of the heating unit itself, the previously describedpermanent expansion joint between the tube 45 to the thin fins 46eifectively prevents significant movement between these members, whilethe embossed structure of the fins prevents them from buckling. The coretube 45 is not clamped to the brackets 27 but is merely supported in thesaddles 29 with ample longitudinal clearance between the brackets andadjacent fins as previously set forth, so that as temperature changesoccur the movement between the tube and brackets may take placegradually in direct response to the increasing or decreasing expansiveor contractive forces, thus minimizing tendency to the production ofsounds at the supporting joints. In addition the fins 46 are spaced fromthe surrounding walls and resilient tape buffers 55 and disposed in thejoints between the main closure plate 4 and the supporting bracket tabs30 and 31 to prevent metal-tometal contact.

The foregoing description of the novel structures and operation of theinvention have been made in connection with two illustrative unitaryembodiments, but it will be readily seen that not only may the device hemade in any desired standard lengths but also that two or more completeunits of the same or different lengths may be combined in a singleinstallation to meet any particular special locational application. Thejunction boxes are provided with back, end and bottom knock-outs 77 asshown in FiGURE 3, promoting convenience in adaptation to availablesupply wiring and in inter-connecting multiple units. The double-endedtype of structure shown in FIGURE 2 obviously permits interchangeableright-hand or left-hand location of supply conductors and thermostats.Furthermore, while electn'cal heating means has been illustrated anddescribed it is evident many of the advantages of the invention may berealized with other heating means as for instance hot water and steam byarranging the finned tubes to be inter-connected with appropriateconduits. Thus while the device has been set forth in typical preferredforms it is not limited to the exact embodiments illustrated, as variouschanges and modifications may be made without departing from the spiritof the invention and the scope of the appended claims.

What is claimed is:

1. A base-board heater, comprising in combination a main housing adaptedto be joined to a wall along the upper border of said housing, saidhousing including a rear partition below said upper border and thermallyinsulated from said wall, a front closure plate spaced from said rearpartition to form therewith a heating chamber having an air inlet belowsaid plate and an air outlet above said plate, said closure plate havinga forwardly inclined perforated lower main face portion spanning thegreater portion of the height of said heating chamber, and a heatingunit supported within said chamber in spaced relation between said rearpartition and said front closure plate.

2. The combination according to claim 1 wherein said closure plateincludes a relatively narrow rearwardly inclined perforated upperportion adjoining said main face portion.

3. In a baseboard heater, in combination, an elongated main housinghaving upper and lower edge portions adapted to be joined to a wall,said housing including a rear partition below said upper edge portionand thermally insulated from said wall, a removable front closure platespaced from said rear partition to define therewith an elongated heatingchamber having an air inlet below said closure plate and an air outletabove said closure plate, said closure plate having a forwardly inclinedperforated lower main face portion spanning the greater portion of theheight of said heating chamber, an elongated electric heating unitsupported in said chamber in spaced relation to said rear partition andsaid front closure plate, means forming an electrical junction box in atleast one end of said housing and a thermostat in said box and inelectrical circuit with said heating unit.

4. In a device of the character described, in combination, an elongatedmain housing member adapted to be joined to a wall along the upper rearlongitudinal edge portion of said member; said member including avertical rear plate portion spaced from said wall to define therewith aconvective flue, a forwardly inclined imperforate portion above andadjoining said rear plate portion and a rearwardly inclined top portionextending from said forwardly inclined portion substantially to saidupper rear edge, said rearwardly inclined top portion being perforatedto provide an air exit from said flue; means forming a bottom air inletto said flue; a plurality of forwardly extending brackets secured tosaid vertical rear piate portion, each of said brackets being formedwith an aperture having a bottom boundary comprising a supporting saddleand having a forwardly extending access slot to said saddle; anelongated heating unit including a central tube normally supported insaid saddles and longitudinally movable freely therein, and a pluralityof thin embossed fins expansively secured to said tube, said unit beingspaced from said rear plate portion; a front closure member removablysecured to said brackets in snap-latch relation and spaced from saidheating unit, said closure member including a forwardly inclinedperforated main face portion and a rearwardly inclined perforated upperportion; and means in at least one end of said device for connectingsaid heating unit to a-source of electric current.

15. The combination according to claim 4 including thin buffer means inthe attachment joints between said front closure and said brackets andresilient sealing means in the joint between said main housing memberedge portion and said wall.

6. Space-heating apparatus including, in combination, a mounting stripadapted to be horizontally secured to a vertical surface at apredetermined height from the foot of said surface, a housing removablyattachable to said strip for support thereby on said vertical surface,said housing having a top including a rear border portion overlying saidstrip when in said attached position, a front cover plate on saidhousing and defining therewith, a lower air inlet to said housing, andan upper air outlet from said housing spaced forwardly from said rearborder portion, and electric heating means in said housing, said frontcover plate having a forwardly inclined perforated main portion insubstantially horizontal alignment with said heating means.

7. In space-heating apparatus, in combination, elongated mounting meansadapted to be secured to a vertical surface at a predetermined heightfrom the foot of said surface; an elongated main housing member, saidmain member including a rear top border portion adapted to overlie andto engage said mounting means to form therewith and with said surface asealing and supporting joint, a forwardly extending perforated topportion adjoining said rear border portion, a rearwardly extendingimperforate portion extending below said perforate top portion, avertical rear wall portion adjoining said inclined portion and spacedbelow and forwardly of said rear border portion to form an air spacebetween said rear wall portion and said vertical surface incommunication with the cavity between said rearwardly inclined portionand said perforated top portion; means forming a lower inlet to said airspace; a plurality of forwardly extending brackets on said rear wallportion; a front closure member detachably carried by said brackets toform with said rear Wall portion a heating chamber having a main airinlet and a main air outlet respectively below and above said'closuremember, said closure member including a forwardly inclined perforatedmain zone and a relatively narrow rearwardly inclined perforated upperzone; a finned electric heating unit supported in free longitudinalsliding relation by said brackets within said heating chamber and spacedfrom the walls of said chamber, said heating unit being bodily removablethrough the front of said chamber; end plates secured to said mainhousing member, and means forming an electrical junction compartment inat least one of said housing assembly.

8. The combination according to claim 7 including thin resilient meansdisposed in said sealing and supporting joint, and resilient silencingmeans at the attachment points between said brackets and said closuremember.

References Cited in the file of this patent UNITED STATES PATENTS1,664,171 Hicks Mar. 27, 1928 1,902,074 Holinger Mar. 21, 1933 2,670,935Arnold Mar. 2, 1954 2,722,403 Guerra et al Nov. 1, 1955 2,733,049 CarterJan. 31, 1956 2,782,007 Glatt Feb. 19, 1957 2,799,763 Hicks July 16,1957 2,815,431 Paley Dec. 3, 1957 2,861,167 Wick Nov. 18, 1958 2,866,070Parks et al Dec. 23, 1958 2,899,529 Calhoun Aug. 11, 1959 2,904,666Jackson Sept. 15, 1959 FOREIGN PATENTS 458,569 Great Britain Dec. 22,1936 493,933 Canada June 23, 1953

